Process for widening and loosening continuous artificial fiber

ABSTRACT

CONTINUOUS ARTIFICIAL FIBER STRANDS ARE WIDENED AND LOOSENED BY MEANS OF A SINGLE OR MULTIPLE PASSES THROUGH AN APPARATUS HAVING A PLURALITY OF ROWS OF NOZZLES. GAS IS BLOWN THROUGH ONE ROW OF NOZZLES AWAY FROM THE CENTER. AND IS BLOWN THROUGH THE ADJACENT ROW OF NOZZLES TOWARD THE CENTER OF THE APLPARATUS.

March 2, 1971 WEIGAND 3,566,451

PROCESS-FOR WIDENING AND LOOSENING CONT'INUOUS ARTIFICIAL FIBER OriginalFiled March 1, 1967 2 Sheets-Sheeti FIG.|

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PROCESS FOR WIDENING AND LOOSENING CONTINUOUS ARTIFICIAL FIBER OriginalFiled March 1, 1967 I 2 Shets-Sheet 2 United States Patent Int. (:1.D01b 3/10 US. C]. 19-66 2 Claims ABSTRACT OF THE DISCLOSURE Continuousartificial fiber strands are widened and loosened by means of a singleor multiple passes through an apparatus having a plurality of rows ofnozzles. Gas is blown through one row of nozzles away from the center,and is blown through the adjacent row of nozzles toward the center ofthe apparatus.

This application is a division of copending application Ser. No.619,774, filed Mar. 1, 1967, now US. Pat. 3,- 444,592.

BACKGROUND OF THE INVENTION The invention relates to a process forwidening out and loosening up an endless or continuous running fiberstrand, for example a strand of cellulose accetate. Fiber strands ofthis kind are employed as cigarette filters for tobacco smoke.

It is known to produce cigarette filters from strands of celluloseacetate which consists of about 10,000 to 20,000 endless fibers, andwhose total titer is preferably between about 35,000 and 90,000 denier.

As a rule these strands possess a more or less intensive crimpingwhereby the individual fibers of the strand stick together so that thestrand possesses only a slight volume. This condition is desiredparticularly for shipment because it permits the accommodation of a highweight in a given small volume.

It is further known to work up such filter strandswhich possess abandlike structureon special so-called filter rod machines into filterrods for tobacco smoke. These filter rods are substantially longer thanthe length of the customary cigarette filter and are later cut into thefilters of the desired length on known machine, in order thereafter tobe combined with the tobacco portion of a filter cigarette.

In the filter rod machine the supplied, still closed and compact filterstrand is broadened out and loosened up to such an extent that the stucktogether fibers are completely loosened from each other and thereby areprepared for uniform reception of the softener.

The part of the apparatus for this portion of the manufacturecustomarily consists of a system of pairs of rolls in front of whichand, if desired, between which there are arranged blower nozzles. Whilethe pairs of rollers have the function of loosening the stuck togetherfibers by means of mechanical pressure, the loosening up of the fiberswith the aid of the blower nozzles is accomplished by means of a more orless undirected gas stream. Nozzles of this kind, for example, consistof a plate having long slits that extend at right angles to thedirection of movement of the strand. This plate rests as ili closureupon the wide end of funnel-shaped air supply nes.

Nozzles of this kind have certain disadvantages. For example, a strongergas stream occurs in the central por- 'ice tion of the nozzle, whereasthe edge portions have a weaker gas stream. This has the result that thestrand which is conducted along these nozzles tends to become thin inthe central portion, whereas accumulations of fibers are formed at theedge portions thereby having a detrimental influence upon the looseningup of the strand and upon the quality of the resultant filter rods.

SUMMARY OF THE INVENTION The subject of the present invention is aprocess for a more uniform distribution of the individual fibers. Inaccordance with this invention, instead of the slitted plate, a platewhich incorporates a system of nozzle holes arranged in rows, wherebythe nozzle holes are so arranged that from row to row alternately theair stream blows in the direction of the righthand and lefthand limitsof the plate, namely outwardly and toward the center, respectively.

This is accomplished by boring the nozzle holes slantingly or at anangle whereby it is of particular advantage to alternate thedistribution of the angle in such a manner that the angle of incidenceof the outermost nozzle holes varies most strongly from the vertical.The minimum requirement is that there be at least two rows of holenozzles. However, their number may be increased as desired. The greaterthe number of rows of hole nozzles, the greater is the loosening upeffect. However, after a certain number of rows of hole nozzles, theloosening up is so good that increasing the number of the nozzle rowsadds practically no advantage and therefore is economically useless. Thediameter of such hole nozzles preferably varies between about 0.2-2.0mm. The nozzles are preferably bored cylindrically. Yet, when specialeffects are desired, conical nozzles may also be employed. Theirdistance from each other may vary between about 1 and 10 mm.Determinative for these measurements is the characteristic of the strandthat is to be worked up, particularly its thickness and its degree ofcrimping.

The above mentioned borings may end directly on the nozzle plate, i.e.in the plane on which the cable runs. It is, however, also possible toarrange them recessed in a groove whereby the depth of this groove mayamount approximately between 0.1-2.0 mm.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is section view through FIG. 2along the line 11;

FIG. 2 is cross-sectional view in elevation of an apparatus according tothis invention; and

FIG. 3 is a schematic and diagrammatic view of an arrangement employingthe apparatus of FIGS. 1-2.

DETAILED DESCRIPTION In FIGS. 1 and 2 the blower nozzle 14 consists ofan outwardly widening funnel 1 whose opening rests upon a gas exit plate2 and is attached thereto by means of screws 3. In this plate 2 areprovided rows of holes 4. The holes are so arranged that one row willblow the introduced compressed gas away from the center (centrifugal),whereas the succeeding row will blow the gas in the opposite directionagainst the middle (centripetal) as shown in FIG. 1. The stem of thefunnel 5 is connected to the supply line 20 for the compressed gas.Through this supply line 20 there is conducted air or some other readilyexpandable gas under pressure into the funnel 1.

The strand of fiber now runs between the gas exit plate 2 provided withthe holes and a cover plate 6. This cover plate 6 is movably attached atone side to the gas exit plate 2 by means of two hinges 7 and arecloseable at the opposite side by means of a bolt 8. The bolt 8 islocked by means of a toggle 9.

The movable cover plate 6 serves inter alia to simplify the introductionof the fiber strand.

Into the gas exit plate 2 and the cover plate 6 a recessed portion 10 iscut out through which the fiber strand runs. The holes 4 of the gas exitplate all open into this recessed portion. The gas coming out of thenozzles escapes from this recessed portion in both directions (upwardlyand downwardly in FIG. 2).

FIG. 3 shows how a strand of fiber 11 is pulled off from a ball orsource of strand 12 in the direction of the arrow. The fiber strand runsover a direction reversing device 13. Between the supply container 12and the direction reversing device 13 there is arranged the blowernozzle 14 (consisting of elements 1-10). The fiber strand 11 now runs atconstant speed through the chamber (recessed portion) 10 of the blowernozzle, whereby air or some other gas under pressure is introduced intothe funnel 1 and through the holes 4. The strand of fiber is loosened upand broadened out in this operation. The loosened up and broadened outfiber strand runs over the reverse direction roller 13 and between twopairs of rollers 15 and 16 into a spray chamber 17. In this spraychamber 17 there is sprayed on to the fiber strand a softener by meansof two opposed spray nozzles 18. The fiber strand which has beenmoistened (wetted) with the softener is now worked up into filter rods.

What is claimed is:

1. A process for broadening and loosening continuous fiber characterizedin passing the fiber through successive blasts of gas which alternate inthe direction in which the gas is directed onto the fiber, with oneblast of gas being directed from the sides toward the center of thefiber and the successive blast being directed from the center toward thesides of the fiber.

2. A process as set forth in claim 1 wherein the alternate blasts of gasemanate from a single device.

References Cited UNITED STATES PATENTS DORSEY NEWTON, Primary Examiner

